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src/java.base/solaris/native/libjsig/jsig.c

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@@ -1,7 +1,8 @@
 /*
- * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2015 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.

@@ -20,139 +21,168 @@
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 
-/* CopyrightVersion 1.2 */
-
 /* This is a special library that should be loaded before libc &
  * libthread to interpose the signal handler installation functions:
  * sigaction(), signal(), sigset().
  * Used for signal-chaining. See RFE 4381843.
  */
 
-#include <stdlib.h>
-#include <stdio.h>
-#include <string.h>
-#include <signal.h>
 #include <dlfcn.h>
-#include <thread.h>
-#include <synch.h>
-#include "jvm_md.h"
-
-#define bool int
-#define true 1
-#define false 0
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
 
-static struct sigaction *sact = (struct sigaction *)NULL; /* saved signal handlers */
-static sigset_t jvmsigs;
+#ifdef SOLARIS
+  #include <synch.h>
+  #include <thread.h>
+#else
+  #include <pthread.h>
+#endif
+
+#if (__STDC_VERSION__ >= 199901L)
+  #include <stdbool.h>
+#else
+  #define bool int
+  #define true 1
+  #define false 0
+#endif
+
+#ifndef NSIG
+  #define NSIG SIGRTMAX
+#endif
+
+static struct sigaction sact[NSIG]; /* saved signal handlers */
+static sigset_t jvmsigs; /* Signals used by jvm. */
+static __thread bool reentry = false; /* prevent reentry deadlock (per-thread) */
 
-/* used to synchronize the installation of signal handlers */
+/* Used to synchronize the installation of signal handlers. */
+#ifdef SOLARIS
 static mutex_t mutex = DEFAULTMUTEX;
 static cond_t cond = DEFAULTCV;
 static thread_t tid = 0;
+#else
+static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+static pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
+static pthread_t tid = 0;
+#endif
 
 typedef void (*sa_handler_t)(int);
 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
-typedef sa_handler_t (*signal_t)(int, sa_handler_t);
+typedef sa_handler_t (*signal_function_t)(int, sa_handler_t);
 typedef int (*sigaction_t)(int, const struct sigaction *, struct sigaction *);
 
-static signal_t os_signal = 0; /* os's version of signal()/sigset() */
+static signal_function_t os_signal = 0; /* os's version of signal()/sigset() */
 static sigaction_t os_sigaction = 0; /* os's version of sigaction() */
 
 static bool jvm_signal_installing = false;
 static bool jvm_signal_installed = false;
 
-
-/* assume called within signal_lock */
-static void allocate_sact() {
-  size_t maxsignum;
-  maxsignum = SIGRTMAX;
-  if (sact == NULL) {
-    sact = (struct sigaction *)malloc((maxsignum+1) * (size_t)sizeof(struct sigaction));
-    memset(sact, 0, (maxsignum+1) * (size_t)sizeof(struct sigaction));
-  }
-
-  if (sact == NULL) {
-    printf("%s\n", "libjsig.so unable to allocate memory");
-    exit(0);
-  }
-
-  sigemptyset(&jvmsigs);
-}
-
 static void signal_lock() {
+#ifdef SOLARIS
   mutex_lock(&mutex);
+#else
+  pthread_mutex_lock(&mutex);
+#endif
   /* When the jvm is installing its set of signal handlers, threads
-   * other than the jvm thread should wait */
+   * other than the jvm thread should wait. */
   if (jvm_signal_installing) {
+#ifdef SOLARIS
     if (tid != thr_self()) {
       cond_wait(&cond, &mutex);
     }
+#else
+    if (tid != pthread_self()) {
+      pthread_cond_wait(&cond, &mutex);
+    }
+#endif
   }
 }
 
 static void signal_unlock() {
+#ifdef SOLARIS
   mutex_unlock(&mutex);
+#else
+  pthread_mutex_unlock(&mutex);
+#endif
 }
 
 static sa_handler_t call_os_signal(int sig, sa_handler_t disp,
                                    bool is_sigset) {
+  sa_handler_t res;
+
   if (os_signal == NULL) {
     if (!is_sigset) {
-      os_signal = (signal_t)dlsym(RTLD_NEXT, "signal");
+#ifdef AIX
+      os_signal = signal;
+#else
+      os_signal = (signal_function_t)dlsym(RTLD_NEXT, "signal");
+#endif
     } else {
-      os_signal = (signal_t)dlsym(RTLD_NEXT, "sigset");
+#ifdef AIX
+      os_signal = sigset;
+#else
+      os_signal = (signal_function_t)dlsym(RTLD_NEXT, "sigset");
+#endif
     }
     if (os_signal == NULL) {
       printf("%s\n", dlerror());
       exit(0);
     }
   }
-  return (*os_signal)(sig, disp);
+  /* On some OSes like macosx, the OS implementation of signal calls sigaction.
+   * Make sure we do not deadlock with ourself. (See JDK-8072147). */
+  reentry = true;
+  res = (*os_signal)(sig, disp);
+  reentry = false;
+  return res;
 }
 
 static void save_signal_handler(int sig, sa_handler_t disp, bool is_sigset) {
   sigset_t set;
-  if (sact == NULL) {
-    allocate_sact();
-  }
   sact[sig].sa_handler = disp;
   sigemptyset(&set);
   sact[sig].sa_mask = set;
   if (!is_sigset) {
+#ifdef SOLARIS
     sact[sig].sa_flags = SA_NODEFER;
     if (sig != SIGILL && sig != SIGTRAP && sig != SIGPWR) {
       sact[sig].sa_flags |= SA_RESETHAND;
     }
+#else
+    sact[sig].sa_flags = 0;
+#endif
   } else {
     sact[sig].sa_flags = 0;
   }
 }
 
 static sa_handler_t set_signal(int sig, sa_handler_t disp, bool is_sigset) {
   sa_handler_t oldhandler;
+  bool sigused;
   bool sigblocked;
 
   signal_lock();
-  if (sact == NULL) {
-    allocate_sact();
-  }
 
-  if (jvm_signal_installed && sigismember(&jvmsigs, sig)) {
+  sigused = sigismember(&jvmsigs, sig);
+  if (jvm_signal_installed && sigused) {
     /* jvm has installed its signal handler for this signal. */
     /* Save the handler. Don't really install it. */
     if (is_sigset) {
-      /* We won't honor the SIG_HOLD request to change the signal mask */
       sigblocked = sigismember(&(sact[sig].sa_mask), sig);
     }
     oldhandler = sact[sig].sa_handler;
     save_signal_handler(sig, disp, is_sigset);
 
+#ifdef SOLARIS
     if (is_sigset && sigblocked) {
+      /* We won't honor the SIG_HOLD request to change the signal mask */
       oldhandler = SIG_HOLD;
     }
+#endif
 
     signal_unlock();
     return oldhandler;
   } else if (jvm_signal_installing) {
     /* jvm is installing its signal handlers. Install the new

@@ -179,35 +209,47 @@
 sa_handler_t signal(int sig, sa_handler_t disp) {
   return set_signal(sig, disp, false);
 }
 
 sa_handler_t sigset(int sig, sa_handler_t disp) {
+#ifdef _ALLBSD_SOURCE
+  printf("sigset() is not supported by BSD");
+  exit(0);
+#else
   return set_signal(sig, disp, true);
+#endif
 }
 
 static int call_os_sigaction(int sig, const struct sigaction  *act,
                              struct sigaction *oact) {
   if (os_sigaction == NULL) {
+#ifdef AIX
+    os_sigaction = sigaction;
+#else
     os_sigaction = (sigaction_t)dlsym(RTLD_NEXT, "sigaction");
+#endif
     if (os_sigaction == NULL) {
       printf("%s\n", dlerror());
       exit(0);
     }
   }
   return (*os_sigaction)(sig, act, oact);
 }
 
 int sigaction(int sig, const struct sigaction *act, struct sigaction *oact) {
   int res;
+  bool sigused;
   struct sigaction oldAct;
 
+  if (reentry) {
+    return call_os_sigaction(sig, act, oact);
+  }
+
   signal_lock();
 
-  if (sact == NULL ) {
-    allocate_sact();
-  }
-  if (jvm_signal_installed && sigismember(&jvmsigs, sig)) {
+  sigused = sigismember(&jvmsigs, sig);
+  if (jvm_signal_installed && sigused) {
     /* jvm has installed its signal handler for this signal. */
     /* Save the handler. Don't really install it. */
     if (oact != NULL) {
       *oact = sact[sig];
     }

@@ -224,11 +266,11 @@
     sact[sig] = oldAct;
     if (oact != NULL) {
       *oact = oldAct;
     }
 
-    /* Record the signals used by jvm */
+    /* Record the signals used by jvm. */
     sigaddset(&jvmsigs, sig);
 
     signal_unlock();
     return res;
   } else {

@@ -239,35 +281,37 @@
     signal_unlock();
     return res;
   }
 }
 
-/* The four functions for the jvm to call into */
+/* The three functions for the jvm to call into. */
 void JVM_begin_signal_setting() {
   signal_lock();
+  sigemptyset(&jvmsigs);
   jvm_signal_installing = true;
+#ifdef SOLARIS
   tid = thr_self();
+#else
+  tid = pthread_self();
+#endif
   signal_unlock();
 }
 
 void JVM_end_signal_setting() {
   signal_lock();
   jvm_signal_installed = true;
   jvm_signal_installing = false;
+#ifdef SOLARIS
   cond_broadcast(&cond);
+#else
+  pthread_cond_broadcast(&cond);
+#endif
   signal_unlock();
 }
 
 struct sigaction *JVM_get_signal_action(int sig) {
-  if (sact == NULL) {
-    allocate_sact();
-  }
   /* Does race condition make sense here? */
   if (sigismember(&jvmsigs, sig)) {
     return &sact[sig];
   }
   return NULL;
 }
-
-int JVM_get_libjsig_version() {
-  return JSIG_VERSION_1_4_1;
-}
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